This invention relates to a system provided within the shell or sealed housing of a compressor for converting high voltage electric power from a single power source to low voltage electric power for powering the auxiliary compressor systems, such as a diagnostic control device.
Compressors are utilized to compress a refrigerant as part of a refrigerant cycle in cooling systems. Modern compressors for refrigerant compression are typically enclosed within a sealed housing. Typically compressors are driven by an electric motor which receives high voltage electric power from an outside electrical power source by way of a power line extending through an opening in the sealed housing. It is essential that all openings through the sealed housing are well sealed to prevent leakage.
Refrigerant compressors operate under extreme conditions and may have relatively complex operational components. Compressor operation presents many design challenges. In addition to the potential for leakage as mentioned above, there is the potential for a variety of operational faults to occur during use as well as during startup and shutdown. For example, an overcharge or undercharge of refrigerant can hinder compressor performance. An improperly wired compressor can also result in compression malfunction.
Typically, compressors have been provided with a plurality of protection devices that sense various performance properties of essential compressor components as compared to predetermined values. The protection devices then respond accordingly in a predetermined manner. For example, the electric motor used for driving a compressor pump is typically provided with a protection switch, which is actuated if a predetermined temperature is reached at which point the motor is stopped. Also, condition responsive valves have been proposed in sealed compressors.
The inventors of this application have recently proposed sensing various performance properties of essential compressor components using a singular diagnostic control device. The diagnostic control device, which is preferably microprocessor based, receives signals relating to a number of operational factors in a compressor. The diagnostic control device is disclosed in patent application Ser. No. 09/553,836, filed Apr. 21, 2000, now U.S. Pat. No. 6,406,265, entitled xe2x80x9cCompressor Diagnostic and Recording Systemxe2x80x9d.
Typically, the compressor elements are driven by an electric motor. The electric motor is housed within the compressor shell and is powered by a high voltage source originating at a point outside the compressor shell by way of a power line received through an inlet opening in the compressor shell.
The microprocessor based diagnostic control device operates using relatively low voltage electric power as compared to the relatively high voltage electric power required to power the electric motor of the compressor. The same is true for the above-mentioned sensors, etc.
Thus, it would be desirable for a low voltage device, such as diagnostic control device, a sensor, etc. to make use of the existing electric power supply that powers the electric motor of the compressor. Thus, the low voltage device can be positioned within the compressor shell without requiring additional low voltage wiring to be fed through any additional openings in the sealed compressor shell.
In the disclosed embodiment of this invention a refrigerant compression system is provided with an electronic circuit to feed low voltage electrical power to a diagnostic control device. The diagnostic control device is positioned within the sealed housing, of the compressor and operates using low voltage electrical power. The low voltage electrical power required to operate the diagnostic control device is obtained from an existing high voltage electric power source that is used to power the motor of the compressor.
The compressor shell is provided with an inlet opening through which a high voltage power line extends. The high voltage power line extends from a high voltage electric power source positioned outside of the sealed compressor shell. Within the compressor shell, the electric power used to operate the diagnostic control device is tapped from the existing high voltage incoming power line, and then converted to the required low voltage electric power. The power is converted using a known conversion circuit preferably including a transformer.
The diagnostic control device is powered with the desired low voltage electric power using the existing high voltage power line. Thus, the necessity to feed additional low voltage wiring through any additional inlet openings in the compressor shell is eliminated.
While the invention is disclosed for powering a diagnostic control device, other low voltage devices such as sensors, etc. can also be powered in this fashion.
These and other features of the present invention can be best understood from the following specification and drawing, the following of which is a brief description.